South Korea's KOSPI posts biggest one-day gain ever after three-day selloff

South Korea's KOSPI index soared 17% on Friday, recording its biggest one-day gain ever as a global tech rally lifted markets. Chipmakers led the rebound, with SK Hynix and Samsung Electronics rising over 23% each, while TSMC gained 10%. The rally eased investor concerns after a three-day AI-driven selloff over doubts about returns on heavy spending.